Over 13 million American men and women of all ages suffer from urinary incontinence. The social implications for an incontinent patient include loss of self-esteem, embarrassment, restriction of social and sexual activities, isolation, depression and, in some instances, dependence on caregivers. Incontinence is the most common reason for institutionalization of the elderly.
The urinary system consists of the kidneys, ureters, bladder and urethra. The bladder is a hollow, muscular, balloon-shaped sac that serves as a storage container for urine. The bladder is located behind the pubic bone and is protected by the pelvis. Ligaments hold the bladder in place and connect it to the pelvis and other tissue. FIG. 2 schematically illustrates female anatomy. The urethra 16 is the tube that passes urine from the bladder 14 out of the body. The narrow, internal opening of the urethra 16 within the bladder 14 is the bladder neck 18. In this region, the bladders bundled muscular fibers transition into a sphincteric striated muscle called the internal sphincter. FIG. 3 schematically illustrates male anatomy. The urethra 16 extends from the bladder neck 18 to the end of the penis 22. The male urethra 16 is composed of three portions: the prostatic, bulbar and pendulus portions. The prostatic portion is the widest part of the tube, which passes through the prostate gland 24.
Incontinence may occur when the muscles of the urinary system malfunction or are weakened. Other factors, such as trauma to the urethral area, neurological injury, hormonal imbalance or medication side-effects, may also cause or contribute to incontinence. There are five basic types of incontinence: stress incontinence, urge incontinence, mixed incontinence, overflow incontinence and functional incontinence. Stress urinary incontinence (SUI) is the involuntary loss of urine that occurs due to sudden increases in intra-abdominal pressure resulting from activities such as coughing, sneezing, lifting, straining, exercise and, in severe cases, even simply changing body position. Urge incontinence, also termed “hyperactive bladder” “frequency/urgency syndrome” or “irritable bladder,” occurs when an individual experiences the immediate need to urinate and loses bladder control before reaching the toilet. Mixed incontinence is the most common form of urinary incontinence. Inappropriate bladder contractions and weakened sphincter muscles usually cause this type of incontinence. Mixed incontinence is a combination of the symptoms for both stress and urge incontinence. Overflow incontinence is a constant dripping or leakage of urine caused by an overfilled bladder. Functional incontinence results when a person has difficulty moving from one place to another. It is generally caused by factors outside the lower urinary tract, such as deficits in physical function and/or cognitive function.
A variety of treatment options are currently available to treat incontinence. Some of these treatment options include external devices, behavioral therapy (such as biofeedback, electrical stimulation, or Kegal exercises), injectable materials, prosthetic devices and/or surgery. Depending on age, medical condition, and personal preference, surgical procedures can be used to completely restore continence. One type of procedure, found to be an especially successful treatment option for SUI in both men and women, is a sling procedure.
A sling procedure is a surgical method involving the placement of a sling to stabilize or support the bladder neck or urethra. There are a variety of different sling procedures. Slings used for pubovaginal procedures differ in the type of material and anchoring methods. In some cases, the sling is placed under the bladder neck and secured via suspension sutures to a point of attachment (e.g. bone) through an abdominal and/or vaginal incision. Examples of sling procedures are disclosed in U.S. Pat. Nos. 5,112,344; 5,611,515; 5,842,478; 5,860,425; 5,899,909; 6,039,686, 6,042,534 and 6,110,101.
Although serious complications associated with sling procedures are infrequent, they do occur. Complications include urethral obstruction, development of de novo urge incontinence, hemorrhage, prolonged urinary retention, infection, and damage to surrounding tissue and sling erosion.
The TVT Tension-free Vaginal Tape procedure utilizes a Prolene™ nonabsorbable, polypropylene mesh. The mesh is a substantially flat, rectangular knitted article. The mesh includes a plurality of holes that are sized to allow tissue ingrowth to help avoid infection. A plastic sheath surrounds the mesh and is used to insert the mesh. During the sling procedure, incisions are made in the abdominal (i.e. suprapubic) area and in the vaginal wall. Two curved, needle-like elements are each connected to an end of the vaginal sling mesh. A sling-free end of one of the needle-like elements is initially pushed through the vaginal incision and into the paraurethral space. Using a handle attached to the needle, the needle is angulated laterally (for example, to the right) to perforate the endopelvic fascia, guided through the retropubic space and passed through the abdominal incision. The handle is disconnected and the needle is then withdrawn through the abdominal wall, thereby threading a portion of the sling through the tissue of the patient. The handle is then connected to the other needle and the technique is repeated on the contralateral side, so that the mesh is looped beneath the bladder neck or urethra. The sling is positioned to provide appropriate support to the bladder neck or urethra. Typically a Mayo scissors or blunt clamp is placed between the urethra and the sling to ensure ample looseness of the sling. When the TVT mesh is properly positioned, the cross section of the mesh should be substantially flat. In this condition, the edges of the mesh do not significantly damage tissue. The sling ends are then cut at the abdominal wall, the sheath is removed and all incisions are closed.
Complications associated with the TVT procedure and other known sling procedures include injury to blood vessels of the pelvic sidewall and abdominal wall, hematomas, urinary retention, and bladder and bowel injury due to passage of large needles. Further, a separate cystoscopy procedure is usually required in order to confirm bladder integrity or recognize a bladder perforation after each insertion of the needle-like element. One serious disadvantage of the TVT procedure, particularly for surgeons unfamiliar with the surgical method, is the lack of information concerning the precise location of the needle tip relative to adjacent pelvic anatomy. If the needle tip is allowed to accidentally pass across the surface of any blood vessel, lymphatic duct, nerve, nerve bundle or organ, serious complications can arise. These shortcomings, attempts to address these shortcomings and other problems associated with the TVT procedure are disclosed in PCT publication nos. PCT WO 00/74613 and PCT WO 00/74594.
Additional problems are associated with the TVT and other sling procedures. Due to the tough fibrous nature of fascia and muscle tissues, forceps or similar instruments are needed to withdraw the needles through the abdominal wall. However, the smooth surface of the needles, which facilitates insertion through the tissues, prevents secure attachment of the forceps onto the needles, causing slippage or detachment of the forceps during the withdrawal procedure. Removal and reuse of the handle of the TVT product is also a cumbersome, time consuming process, requiring the surgeon to manually rotate the handle until the handle is unscrewed from the needle. Reusing the handle presents a contamination risk, particularly if the handle and screw threads are not properly cleaned and sterilized after use on one side of the patient.
The problems associated with improper placement of the TVT mesh are particularly troublesome. If the mesh is too loosely associated with its intended physiological environment, the mesh may be ineffective in supporting the urethra and treating incontinence. Several complications can arise from a mesh that is too tightly placed including retention, sling erosion and other damage to surrounding tissue such as the urethra and vagina.
Once the sheath is removed from the mesh of the TVT product, friction between the mesh and tissue keeps the mesh in position and it becomes very difficult to subsequently adjust the position of the mesh relative to tissue. Because the tension of the sling is an important part of the sling procedure, surgeons will nonetheless attempt to adjust the tension of a sling even after the sheath is removed. TVT mesh is elongate, substantially flat and elastic. When pulled on longitudinally, the TVT mesh deflects elastically. If insufficient adjustment force is applied, the sling will simply exhibit a memory property and return to its original, unacceptable position. As a result, surgeons are tempted to use a great deal of force in order to loosen a sling that is perceived to be too tightly associated with its intended physiological environment. If excessive force is applied, the mesh will plastically deform and the cross section of the mesh will become arcuate. Under excessive deformation, the holes of the TVT mesh become significantly smaller, and risk deterring tissue ingrowth. Without tissue ingrowth, the potential for infection is believed to increase. In the excessively deformed state, the edges of the mesh tend to curl up and present a relatively sharp, frayed surface. In this curled or deformed state, the edges of the TVT mesh present sharp surfaces that can readily abrade or otherwise damage adjacent tissue such as the urethra, bladder or vagina.
Attempts to reposition the TVT sling are likely to fail in two modes. First, the surgeon may apply insufficient elongation force to the mesh (e.g. with forceps), resulting in temporary elastic deformation of the mesh followed by a return by the mesh to its original, unacceptable position after the force is removed. Second, the surgeon may apply excessive force to the mesh resulting in the curling deformation described above with the attendant risk of tissue damage. Additionally, an axially deformed sling necks down (i.e. decreases in width) and provides less cross sectional area to support the urethra. Thus, even if the edges do not curl, excessive deformation of the TVT sling risks adversely affecting sling performance. In the case of an improperly positioned sling, some surgeons will cut the TVT mesh and attempt to remove the mesh as reported in the literature.
There is a desire to obtain a minimally invasive yet highly effective device that can be used with minimal to no side effects. Such a device should reduce the complexity of a sling procedure, be biocompatible, adjustable, and non-toxic. The treatment methods using the device should reduce pain, operative risks, infections and post operative hospital stays. Further, the method of treatment should also improve the quality of life for patients.